Ultrasound features of multinodular goiter in DICER1 syndrome

DICER1 syndrome is caused by germline pathogenic mutations in the DICER1 gene. Multinodular goiter (MNG) is a common clinical feature of DICER1 syndrome in children and adults. The aim of this study was to determine the ultrasound (US) characteristics of MNG in patients with DICER1 syndrome. This retrospective study evaluated thyroid US in patients with DICER1 germline mutations (DICER1mut+) performed between 2011 and 2018 at a single center by the same pediatric endocrinologist, and the images were re-examined by an independent pediatric radiologist from another academic center. Patients < 18 years with DICER1mut+ and DICER1mut+ parents without previous thyroidectomy were included. Ultrasound phenotypes of MNG in the setting of DICER1 mutations were compared with known US features of thyroid malignancy. Thirteen DICER1mut+ patients were identified (10 children, 3 adults). Three children had a normal thyroid US; therefore, thyroid abnormalities were assessed in seven children and three adults. In both children and adults, multiple (≥ 3) mixed (cystic/solid) nodules predominated with single cystic, single cystic septated and single solid nodules, occasionally with a "spoke-like" presentation. All solid lesions were isoechogenic, and in only one with multiple solid nodules, intranodular blood flow on power/color Doppler was observed. Remarkably, macrocalcifications were present in all three adults. The spectrum of ultrasonographic findings of MNG in DICER1mut+ patients is characteristic and largely distinct from typical features of thyroid malignancy and therefore should inform physicians performing thyroid US of the possible presence of underlying DICER1 syndrome.